Blisters form from friction on your skin so dont wear clothes that will rubb roughly on your skin, or that are too tight. And if you think your shoes will give you blisters then wear a bandaid on your heel, or where ever. BEFORE a blister forms. Or if its your hands from climbing, carrying etc. then wear gloves maybe...
for healing blisters i dont know, just put polysporin and a bandaid on.
well if its from working out side or sumthing then ur ganna get them no matter. but if its from playing drums or gutair. well for gutair ur ganna get them till u play alot but from drums u can use rubber handles for the sticks
to prevent them: stay hydrated...drink lots of water, especially in hot weather and also avoid wearing tight clothing.